1. Field of the Invention
The present invention relates to a display panel in which input sensitivity is improved for efficiently detecting the input coordinate values of a touch by a user.
2. Description of the Related Art
A touch screen panel is an information input means which inputs information when a user touches a screen. The touch screen panel is installed on an image display surface of a display device such as a liquid crystal display (LCD) device, a field emission display (FED) device, a plasma display panel (PDP) device, and an electro luminescence (ELD) device.
The touch screen panel is greatly classified into a capacitive touch screen panel and a resistive touch screen panel. The capacitive touch screen panel has one transparent conductive film or glass for storing electrical charges. When the touch screen panel is touched by, e.g., a stylus, a small amount of charge is drawn to a contact point between the stylus and the transparent conductive film. The amount of charge detected at the contact point is converted into coordinate values. In the resistive touch screen panel, if a user touches a screen in a state that a voltage is applied to two opposite conductive layers, the two conductive layers contact, and a change in voltage or electrical current occurs at the contact point. The change in voltage or electrical current is detected and converted into coordinate values.
In case of the capacitive touch screen panel, electricity should be supplied to a stylus. For this reason, the resistive touch screen panel of an analog input method, which is constructed integrally with an LCD panel, is usually used. The resistive touch screen panel may be formed inside an LCD panel in order to prevent brightness of the LCD panel from being degraded.
In an LCD panel with an integrated touch screen panel, first touch conductive lines and second touch conductive lines are formed in a matrix form in a thin film transistor (TFT) array substrate so that a first coordinate value which represents a horizontal contact point and a second coordinate value which represents a vertical contact point can be detected. Also, a touch spacer which contacts the first and second touch conductive lines is formed in a color filter array substrate. In case of a conventional LCD panel with an integrated touch screen panel, there is a problem in that detecting error is frequently caused because the touch sensitivity is low when the touch spacer is contacting the thin film transistor array substrate. When too much pressure is used to compensate for the low sensitivity, the panel reliability degrades.